General description The Blue Spot Tools 6 Piece HSS Countersink Set is designed for precision drilling and countersinking in various materials. This set includes six high-speed steel (HSS) countersinks, ranging from 6.3mm to 20.5mm, making it ideal for both professional and DIY projects. Technical specifications Material: High-Speed Steel (HSS) Sizes included: 6.3mm, 8.5mm, 10.5mm, 12.5mm, 16.5mm, 20.5mm Usage This countersink set is perfect for creating a conical hole for screws, allowing them to sit flush with the surface. It can be used on various materials, including wood, plastic, and soft metals.